Why Would a Carbon Monoxide Alarm Go Off?

A carbon monoxide (CO) alarm sounding is a serious indication that dangerous levels of carbon monoxide are present in your home. The alarm is designed to alert you to this odorless, colorless, and potentially deadly gas before it causes significant harm, and ignoring it can be fatal.

Understanding the Silent Killer: Carbon Monoxide

Carbon monoxide is produced by the incomplete combustion of fuels, such as natural gas, propane, wood, kerosene, and gasoline. Common sources in homes include:

• Furnaces
• Water heaters
• Fireplaces
• Stoves
• Portable generators
• Cars left running in attached garages

When these appliances malfunction or are improperly vented, CO can build up inside your home. Because CO prevents your blood from carrying oxygen, exposure can lead to symptoms such as headaches, dizziness, nausea, and even death.

Potential Causes: Digging Deeper

A CO alarm going off doesn’t always mean a catastrophic leak. There are several possibilities:

• Malfunctioning appliance: This is the most common reason. Furnaces, water heaters, and other fuel-burning appliances should be inspected and serviced annually to ensure they are working correctly. Cracks in the heat exchanger of a furnace are a frequent culprit.

• Improper ventilation: Blocked chimneys, vents, or flues can prevent CO from escaping, leading to a buildup inside the home. Regular inspections and cleaning are crucial.

• Using fuel-burning appliances indoors: Using a gas grill, charcoal grill, or generator inside a home or garage can quickly lead to dangerous CO levels. These appliances should only be used outdoors.

• Backdrafting: This occurs when air flows in the opposite direction than it should in a chimney or flue. Backdrafting can pull exhaust gases, including CO, back into the home. It can be caused by negative pressure created by running exhaust fans (like bathroom fans and range hoods) simultaneously in a tightly sealed home.

• Alarm malfunction: While less common, CO alarms can fail or reach the end of their lifespan (typically 5-7 years). Replace alarms according to the manufacturer’s instructions. Some alarms have a “fault” indicator that will trigger the alarm even when no CO is present.

• Temporary CO spikes: Activities like starting a car in an attached garage or using a fireplace can cause temporary CO spikes. If the alarm sounds briefly and then stops, and no symptoms are present, this could be the cause. However, it’s crucial to investigate the source.

Immediate Actions: Protecting Yourself and Your Family

If your CO alarm sounds, take these steps immediately:

1. Evacuate: Immediately leave the premises with everyone inside, including pets.

2. Call Emergency Services: From a safe location outside the building, call 911 or your local fire department. Do not re-enter the building until emergency personnel have determined it is safe.

3. Do Not Ignore: Even if you don’t experience symptoms, treat the alarm as a serious threat.

4. Ventilate: If emergency personnel determine the CO levels are low but still present, ventilate the home by opening windows and doors.

5. Professional Inspection: Schedule a professional inspection of your fuel-burning appliances to identify and correct the source of the CO.

Frequently Asked Questions (FAQs)

What is the difference between a CO alarm and a smoke detector?

CO alarms detect carbon monoxide, an odorless and colorless gas produced by burning fuel. Smoke detectors detect smoke particles in the air, indicating a fire. Both are essential for home safety but serve different purposes. A combination smoke/CO alarm can offer both protections in one device.

Where should I install CO alarms?

Install CO alarms on every level of your home, including the basement. Place them outside sleeping areas, ideally within 10 feet of bedroom doors. Follow the manufacturer’s instructions for placement as some alarms have specific height recommendations.

How often should I test my CO alarm?

Test your CO alarm at least once a month by pressing the test button. Replace the batteries as needed, typically annually, unless you have a unit with a sealed 10-year battery.

How long do CO alarms last?

Most CO alarms have a lifespan of 5-7 years. Check the manufacturer’s instructions or the date printed on the alarm to determine when it needs to be replaced.

What are the symptoms of carbon monoxide poisoning?

Symptoms of CO poisoning can be flu-like and include:

• Headache
• Dizziness
• Nausea
• Vomiting
• Weakness
• Confusion
• Blurred vision
• Loss of consciousness

High levels of CO can cause death.

Can I use a CO alarm in my RV or boat?

Yes, CO alarms are crucial for RVs and boats, as they also contain fuel-burning appliances. Install them according to the manufacturer’s instructions and ensure they are tested and maintained regularly. Marine-grade CO alarms are specifically designed for the harsh marine environment.

What should I do if my CO alarm keeps beeping but no one is feeling sick?

This could indicate a low battery, a malfunctioning alarm, or the presence of low levels of CO. Replace the batteries first. If the beeping continues, replace the alarm. If possible, call your local fire department to inspect your home for CO levels.

Can a faulty appliance cause a CO alarm to go off intermittently?

Yes, a faulty appliance can cause intermittent CO leaks, leading to sporadic alarm activations. Don’t ignore intermittent alarms – have your appliances inspected by a qualified technician.

What is backdrafting, and how can I prevent it?

Backdrafting occurs when air flows in the opposite direction than it should in a chimney or flue, pulling exhaust gases (including CO) back into the home. To prevent it:

• Ensure proper venting of appliances.
• Have chimneys and flues inspected and cleaned regularly.
• Avoid creating negative pressure by running multiple exhaust fans simultaneously in a tightly sealed home.
• Consider installing a draft inducer to improve chimney draft.

My neighbors had a CO leak. Should I be concerned?

If your neighbors had a CO leak, it’s wise to be cautious. While CO leaks are typically localized, it’s prudent to:

• Ensure your CO alarms are working properly.
• Inspect your own fuel-burning appliances.
• Be aware of the symptoms of CO poisoning.

Are there different types of CO alarms?

Yes, there are different types of CO alarms:

• Battery-operated: These are the most common and require battery replacements.
• Hardwired: These are connected to your home’s electrical system and often have a battery backup.
• Smart CO alarms: These connect to your home’s Wi-Fi network and can send alerts to your smartphone.

What is the legal requirement for CO alarms?

Many states and municipalities have laws requiring CO alarms in residential buildings. Check your local regulations to ensure you are in compliance. Even if not legally required, CO alarms are a crucial safety measure.